Telephone-exchange system.



v L. H. JOHNSON. TELEPHONE EXCHANGE SYSTEM.

APPLICATIGN men JULY24, me. I

Patented Jan. 16, 1917.

ff? yer/for:

%TATE% @ft li ifll LEWIS H. JOHNSON, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, 012' NEW YORK, N. 1 A CORPORATION OF NEW YORK.

TELEPHGNE-EXCHAN GE SYSTEM.

To all whom it may concern:

Be it known that I, Lnwrs H. JoHNsoN,

a citizen of the United Stat-es, residing at Bloomfield, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone Exchange Systems, of which the following is a full, clear, concise, and exact description. I

This invention relates to telephone exchange systems and more particularly to such systems which employ automatic ringing for signaling purposes and which are provided with trunk lines extending to private branch exchanges, chief operators desks and like positions.

As applied to ordinary subscribers lines, automatic or keyless ringing has proven very satisfactory, but when employed in signaling between different operators positions, for instance, between central oiiice and private branch exchanges or between an answering operator and a chief operators or wire chief's desk, the method of signaling by means of automatic ringing has been found to possess an inherent defect which manifests itself in the form of an objectionable click in the ears of the signaled and answering operator. This 0 3O jectionable click is'due to the inclusion of the answering operator's receiver directly in the circuit upon which ringing current is being impressed, when the listening key is actuated in response to a call. The ringing current is cut off innncdiately upon the inclusion of the receiver in circuit therewith, but not lwfore it has given the operator the disagreeable click, which is due' to the action of the central oflice mechanism 40 in transferring the trunk leads from the source of ringing or alternating current to the source of direct current upon the actuation of the listening key. This objectionable click is not met with in signaling an ordinary subscriber, for the reason that the mechanism at the central ofiice operates to disconnect ringing current from the line and substitute talking current therefor in the interval between the time the subscriber removes the receiver from the sWitchhook and the time it is placed to the ear of the subscriber.

It is very desirable that thisobjectionable and disagreeable feature be eliminated,

Specification of Letters Patent.

Patented Jan. 316, 1293?.

a lication filed July 24, 1916. Serial No. 111,010.

and this invention has that purpose for its object.

In accordance with this invention, when an operator answers a call by actuating a listening key, a quick operating and slow releasing relay is operated to disable the answering operators receiver, and maintain this receiver disabled until after the ringing current has been cut off and talking current substituted therefor, and the operators telephone set connected with the trunk circuit. I

This invention is illustrated in the accompanying drawing in which all apparatus is shown in its normal and unactuated condition.

There is shown in the drawing a telephone exchauge system containing one embodiment of this invention, and comprising a cord circuit A located at one section C of a switchboard, and a trunk circuit- B extending from this section C to a desk operators position D, at which there is a signaling device, a listening key and an operators telephone set. It is believed that this invention will be fully understood from a description of the operation of the system shown in the drawing, and it will be so described.

lhe operator at section C. desiring to signal the desk operator 1), inserts a plug 5 into a jack (3, whereupon lamp 7 will be lighted and relay 8 operated. tion of relay 8 causes the actuation of a ringing relay 9 over a circuit from battery through resistance 10, winding of relay 9, normal contact of relay 11, contact of trip relay 12 and the closed contact of relay 8 to ground. The operation of ringing relay 9 connects a source of ringing current 15 to the trunk circuit B, causing the operation of relay 16 over a circuit from the source of ringing current 15 through the winding of trip relay 12, lower alternate contact of ringing relay 9, ring contacts of plug 5 and jack (3, condenser 17, right-hand winding of relay 16, tip contacts of jack 6 and plug and upper alternate contact of ringing relay 9 to ground. The operating winding of relay"16 is of high impedance, so that trip relay 12 is not actuated when in circuit with relay 16. Upon the -actuation of relay 16, it is locked up over a circuit from battery through the left-hand winding and The operaoperates,

' and Winding and contact 28 of thereof mail the normally closed cosifiecf of lisizeiiino key 1 to ground lemp is ligh' d upon il'ic ocicetion reiey 3o furnish a cl .co the i 4?: eratoi', remains 11g, lied ii'ntii filie the lisiening l ey F5.

,3! cement also remains coonecceci L the trunk circuit until the actuation of the listening key 18 by the desk operafior.

The desli". operator, upon OlJSGIi' lighted. conilvL-ion of lamp 19, ames is toning key 18 which opens the ioolring circuit relay 16 and the circuit of lanip l9, therein extinguishing the lamp. The ectum tion of listening key 18 causes the operation of a quick operating and slow releasing i'elay 25 over a circuit from hotieiy tiiirough the winding of 25, lower normal contact of relay 28, concoct of relay 2'7, oonieco 28 of key 18 to ground, Relay 2;), in

I operating, shorocircuiis the desk opera tor s receiver 29, mil moi i'eins this short oircliit until the ringi' current is tripped and the operotorle telepoone set is co with. izlie trunk circuit, will her i. more fully Eyfizhe ec' buoizion of a slow operating relay is included in circuit toiling liogr' l8, ow impezionce source oi ringing current 15, so thatcrip relay 12 27ml relay 2? operate. Belay 12, in operet opens its contact, removing a short circuit from and permitting relay 1 izo operate. Relay 11 is thereupon locke rl'up over a circuit fi'om baiiery through resistance 10, alternate Contact and windin of relay 11 and concoct of relay 8 to groan .The operation of relay 11- szlso establishes a short circuit for the ringing relay 9, which chereiipon releases, removing ringing current from the trunk circuit. The operation of relay 2'? opens iils contact, thereby removing a short oircuic 'from.and permitting che eoesogizo tion of relay 26 over the circuit inclu iing relay 25 and Contact 28 of key 18. When relay '26 looks up over a circuit from battery, through its alternate contact listening key 18 to ground and establishes a shortcircuit for relay 25 which is thereupon deprived of current. The opemtion of relay 26 else closes contact 31 in che talking circuit thereby connectin' the opem'oors telephone see With' the tl'lll'i fl'ell'culfi, but, since relay 25 is slow in releesing, oontoctgl is closecl and supervisory relay 30 operates before the short circuit is IGETiW/"Qd om the leek operators receiver 29, thereby preventing any objectionable and disagreeable clicks iio fihe receiver. The operating circuit sizpeo visory relay 30 he z'fiiiaceol from baht-cry through Winding 32 of re ocating coii 33, Winding of supervisory relay 30, lower 11oz:- mei contact. of ringing relay 9, ring contecfis of plug and jack 6, conteci, 34,- of liseening key 1%, com,

come.

- M H, V'L a 1 pane mm ice 1 1 4' c iicli 18 thereby eiiacctl, incliceimg;

rotor at section or position =3 time I is ope 'ecor D has ensweieii.

What is chimed is:-

I, The combination two te ephone switchboards connected together a pair confiuctore, means at one of adopted to complete a circuit for doctors to apply curve ci conduceors. to said? other evioe opermfiec'i' thereby, e iisc UMLUES receiver, e relay opereteci upon he actuation of the listening key to short circuit the receiver, means for disconneco ringing current from she oircui'Qoml e. ole? operating thereupon to include the op i ors fielephoroe set in the circuit op .zv'zion of said second menzionecl permitting: the fiZSiZ mentioned relay lease eoci remove the short circiiie fiom receiver. 7

A exchange system comprising a pair of coiicloetois joining SWilfill" boards, e source of ringing current one board, means thereoi for impressing cowent from soii'rce over soiil conclucitore, e ing; ceviee at the ohei' booed operated thereby, anopemizors telephone set fish erect, a listening key, a relay opera-ted upon the actuation of the listening lreyio eote'blish a short circuit for the receiver of the operaors set, rendei'ed efieciive loy the achiefiion of the listening key so disconnect the ringing current from circuit, and means operating-thereupon to l'llfiitlfi) the telephone in circuit with COIIClIlciZQZS and thereefier remove the short Cifliifij from the receiver.

3, A telephone exchange sys'isom commie ing e crueloircui; extending from one telephone switchhoerd; at one of ssiiei boards for opplying i'ioging correct owe? trunk to i'iie oihci hoard,

switch ec'cuated board for disconnoeimgihe current from w crook, on operetofis celephone moons ooei etecl moon the actuation of" .1.

Mimi: GIiFTGi'I' removal of: Elm fillcilltmore ing a in coil; exteiioiioo' ghee-e switcoboorcl 0 5 eeco at one ox seiil boards for m1 1,. c 1. heiopoooe exchange syswic Y to o secoml hoorgl, means by the opei eeoi that current over said trunk to the other board, a switch actuated by the operator at that hoard for disconnecting the ringing curs ren from the trunll, an operatorstelephone set, a relay operated by the actuation of the switch to short-circuit the receiver of the operators telephone set, and means operating upon the removal of the ringing current to connect'the operato1"s telephone set to the trunk circuit and thereafter cause the removal of the short circuit from the receive'r.

5. A telephone exchange system comprising a trunk circuit extending from one telephone switchboard to a second board, means at one of said boards for applying ringing I current over said trunk to the other board,

a switch actuated by the operator at that board for disconnecting the ringing current from the trunk, an operators telephone set, a relay operated by the actuation of the switch to short-circuit the receiver of the operators telephone set, and a relay operat ing upon the removal of the ringing current to connect the operators telephone set to the trunk circuit and thereafter cause the removal of the short circuit from the receiver.

6. A telephone exchange system comprising a trunk circuit extending from one telephone switchboard to a second board, means at one oi said boards for applying ringing current over said trunk to the other board, a switch actuated by the operator at that board for disconnecting the ringing current'froni the trunk, an operators telephone set, means operated upon the actuation of the switch to shortcircuit the receiver of the operators telephone set, and a relay operating upon the removal of the ringing current to connect the operators telephone set to the trunk circuit and thereafter cause the removal of the short circuit from the receiver.

T. A telephone exchange system comprising a trunk circuit extending from one telephone switchboard to a second board, means at one of said boards for applying ringing current over said trunk to the other board. a switch actuated by the operator at that board for disconnecting the'ringing. current from the trtink, an operators telephone set, a slow release relay operated upon the my name this 22d day of July, A.

actuation of the switch to short-circuit a. receiver of the operators telephone set, an a relay operating upon the removal of th ringing current to connect the operator s telephone set to the trunk circuit and to divert current from the slow release relay.

8. A telephone exchange system ornprising trunk circuitextending from one telephone switchboard to a second board, means at one o1 sai d boards for applying ringing current over said trunk to the other board, a switch actuated. by the operator at that board for disconnecting the ringing current from the trunk, an operators telephone set, means operated upon the actuation of the switch to disable the receiver of the operators telephone set, and means operating after the removal of the ringing current connect the operatorh telephone set'to the trunk circuit and thereafter render the dis-- abling means ineffective. e

9. A telephone exchange system comprising a trunk circuit extending from one telephone switchboard to a. second board, means at one of said boards for applying ringing current over said trunk to the other board,

an operators telephone set at said other board, a switch thereat actuated by the operator for connecting the operators telephone set to the trunk and for disconnecting the ringing current from the trunk, and means for disabling the receiver of the operators' telephone set during the period in which the ringing current is being removed.

10. a telephone exchange system comprising a trunk circuit extending from one telephone switchboard to a second board, means at one of said boards for applying ringing current over said trunk to the other board, an. operators telephone set at said other board, an operator-controlled switching device thereat actuated for connectinglthe operators telephone set to the trunk end-tor disconnecting the ringing current from trunk, and a relay controlled by the switching device for temporarily disabling the re ceiver of the operators telephone set during the period in which-ringing current is being removed.

In witness whereof, I hereunto subscribe 191".

LEWIS H. JOHNSON.

C te 

